INDUCTION OF ANTI-DNA ANTIBODIES IN NON AUTOIMMUNE MICE BY IMMUNIZATION WITH A DNA-DNAASE-I COMPLEX

Recent studies suggest that anti-DNA antibodies may arise from the imm une response to a complex of DNA and a DNA-binding protein. One of the protein targets frequently recognized by anti-DNA antibodies is the e nzyme DNAase I. To investigate the possible role of DNAase I in the in duction of anti-DNA antibodies, we immunized mice with a complex of DN A and DNAase I. Mammalian double strand DNA was crosslinked with DNAas e I by ultraviolet light (UV) treatment and emulsified in complete Fre und's adjuvant. BALB/c mice were immunized at the base of the tail wit h the DNA-DNAase complex, boosted after 2 weeks with the immunogen in incomplete adjuvant and bled one week after the boost. Control mice re ceived UV treated DNA in adjuvant. In one-third of the mice immunized with the DNA-DNAase complex, IgG anti-DNA antibodies were detectable i n serum; the antibodies reacted with single and double strand DNA. No anti-DNA response was elicited by immunization with DNA alone. These d ata show that immunization with a DNA-DNAase complex can induce anti-D NA antibodies in non-autoimmune mice strains and suggest that DNA-bind ing proteins may act as carriers in the immune response that beads to anti-DNA antibody production.